http://cplusplus.com/forum/general/38064/

xd13

#include <iostream>
#include <cmath>
#include <cstdlib>
#include <iomanip>

using namespace std;

void foo(int, int, double, double);
double calculate_CI(int, int, double, double);

int main()
{
    int years, timesCompounded; //The number of years deposited, the number of times per year compounded
    double interestRate, principal; //The nominal annual interest rate, the amount of money deposited.
    years = 10;
    timesCompounded = 4;
    interestRate=5;
    principal = 100;
    foo(years, timesCompounded, interestRate, principal);
    years = 20;
    timesCompounded = 12;
    interestRate=5;
    principal = 100;
    foo(years, timesCompounded, interestRate, principal);
    years = 50;
    timesCompounded = 365;
    interestRate=5;
    principal = 100;
    foo(years, timesCompounded, interestRate, principal);
    system ("pause");  /* Only on MS Windows */
    return 0;
}

double calculate_CI(int y, int t, double i, double p) {
    return (p * pow(1+i/(100*t), t*y));
}

void foo(int y, int t, double i, double p) {
    cout<<"If you deposit "<<p<<" at "<<i<<" nominal annual interest rate ";
    cout<<"compounded "<<t<<" times per year for " <<y<<" years,\n";
    cout<<"you will have "<< fixed << setprecision(2) << calculate_CI(y,t,i,p) <<" in your account.\n";
}